Skip to content

[Flang] - Enhance testing for strictly-nested teams in target regions. #168437

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Nov 25, 2025
Merged

[Flang] - Enhance testing for strictly-nested teams in target regions. #168437

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
fb029d2
[Flang] - Enhance testing for strictly-nested teams in target regions.
bhandarkar-pranav Nov 17, 2025
5c76ada
use topTeamsSet not allTeamsSet
bhandarkar-pranav Nov 17, 2025
bfac21f
Remove unnecessary print from testcase
bhandarkar-pranav Nov 20, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 9 additions & 0 deletions flang/lib/Semantics/check-omp-loop.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -262,6 +262,15 @@ void OmpStructureChecker::Enter(const parser::OpenMPLoopConstruct &x) {
EnterDirectiveNest(SIMDNest);
}

if (CurrentDirectiveIsNested() &&
llvm::omp::topTeamsSet.test(GetContext().directive) &&
GetContextParent().directive == llvm::omp::Directive::OMPD_target &&
!GetDirectiveNest(TargetBlockOnlyTeams)) {
Comment on lines +265 to +268
Copy link
Member

@ergawy ergawy Nov 20, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Not exactly relevant to this PR since a similar check is used somewhere else. But for the following example:

!$omp target ....
  !$omp teams ....
    !$omp target ....
      .... some statement ....
      !$omp teams ....
        ....
....

Would the semantic check trigger in this case? I think it won't since GetDirectiveNest(TargetBlockOnlyTeams) will return a non-zero result.

Copy link
Contributor Author

@bhandarkar-pranav bhandarkar-pranav Nov 20, 2025 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I coudn't nest a target directive inside the teams directive because that is not allowed, but I did the following

 !$omp target map(tofrom:counter)
   !$omp teams
    !$omp parallel
      !$omp target
        ... some stmt...
       !$omp teams
        .... a structured block...
       !$omp end teams    
      !$omp end target
    !$omp end parallel
   !$omp end teams
  !$omp end target

This compiled fine but it shouldn't have for the reason you mentioned. Strangely enough, gfortran also accepts the code above, only warning about reverse-offloading. I am torn between spending time fixing it on the one hand while on the other hand letting what seems to be an obscure case slide.

Copy link
Member

@ergawy ergawy Nov 24, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I am torn between spending time fixing it on the one hand while on the other hand letting what seems to be an obscure case slide.

No need to fix it, at least in this PR. Specially since the test is used somewhere else. The way the directive-nest test is currently implemented is just surprising to me (seems a bit too permisive) and wanted to verify if this is really the case.

context_.Say(GetContextParent().directiveSource,
"TARGET construct with nested TEAMS region contains statements or "
"directives outside of the TEAMS construct"_err_en_US);
}

// Combined target loop constructs are target device constructs. Keep track of
// whether any such construct has been visited to later check that REQUIRES
// directives for target-related options don't appear after them.
Expand Down
7 changes: 7 additions & 0 deletions flang/lib/Semantics/check-omp-structure.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5215,6 +5215,13 @@ bool OmpStructureChecker::CheckTargetBlockOnlyTeams(
if (dirId == llvm::omp::Directive::OMPD_teams) {
nestedTeams = true;
}
} else if (const auto *ompLoopConstruct{
std::get_if<parser::OpenMPLoopConstruct>(
&ompConstruct->u)}) {
llvm::omp::Directive dirId{ompLoopConstruct->BeginDir().DirId()};
if (llvm::omp::topTeamsSet.test(dirId)) {
nestedTeams = true;
}
}
}

Expand Down
20 changes: 20 additions & 0 deletions flang/test/Semantics/OpenMP/target-teams-nesting.f90
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
! RUN: %python %S/../test_errors.py %s %flang_fc1 -fopenmp

program main
implicit none
integer, parameter :: n = 100
integer, parameter :: expected = n+2
integer :: i
integer :: counter

counter = 0
!ERROR: TARGET construct with nested TEAMS region contains statements or directives outside of the TEAMS construct
!$omp target map(tofrom:counter)
counter = counter+1
!$omp teams distribute reduction(+:counter)
do i=1, n
counter = counter+1
end do
counter = counter+1
!$omp end target
end program